Find the ages of the three sisters

Question

The ages of three sisters are consecutive integers. If the sum of the three sisters age is 54,how old are the three sisters?

Answer 1

let's say S is the age of the youngest sister. Then the age of the middle sister is S + 1, and the age of the oldest sister compared to the youngest is S + 2

 

we have

54 = S + (S+1) + (S+2)

which is the same as

54 = 3S + 3

 

divide both sides by 3

54 / 3 = S + 1

18 = S + 1

 

subtract one from both sides

17 = S

 

check

54 = 17 + 18 + 19